In the international standard classification, en 2.1 involves: .
IEC - International Electrotechnical Commission, en 2.1
IEC 60688:1997 Electrical Measuring Transducers for Converting a.c. Electrical Quantities to Analogue or Digital Signals (Edition 2.1; Edition 2: 1992 Consolidated with Amendment 1: 1997)
未注明发布机构, en 2.1
DIN EN 301025:2017 VHF radiotelephone equipment for general communications and associated equipment for digital selective calling (DSC) Class D – Harmonized EN containing the essential requirements of Articles 3.2 and 3.3(g) of EU Directive 2014/53/EU (recognition of the En